Through its broad attempt to shut down Internet communications, Egypt's government has not only successfully blocked Twitter but also significantly limited access to Facebook, Yahoo and Google, as it scrambles to squelch political unrest.

While it's not the first time a government has resorted to censoring online content and blocking Internet access, Egypt's actions have caught the attention of the world because they're out of character and because they've been so aggressive.

"Prior to this incident, the Egyptian government had blocked only minimally: opposition sites, but no social media or international news," said Jillian York, a project coordinator at Harvard University's Berkman Center for Internet & Society, via e-mail.

"The government does not have a central control point for the Internet, which means it must rely on being able to force ISPs to comply," she said, adding that, to her knowledge, there was still one ISP (Internet service provider) operating on Friday afternoon.

Clearly, what's rattled the government is the major role that social media has played in the protests rocking the country's cities, including Cairo.

"Facebook, Twitter, YouTube, and even Google Docs have been used in unprecedented ways this time around -- both for coordination, and for disseminating news," York said.

She and others are skeptical over the effectiveness the Internet crackdown will have on the civil unrest at this point.

"Twitter, Facebook, and the Internet have made civil disobedience more efficient," said industry analyst Rebecca Wettemann from Nucleus Research. "The government is reacting to a civil problem by cutting one channel of communications, and there are always other ways."

In the meantime, Egypt is getting a black eye abroad, especially in the business community, Wettemann said. "This knee jerk reaction shows Egypt's not open for business -- and will likely have dramatic negative consequences for the companies doing business there," she said.

Earlier this week, the Egyptian government targeted Twitter, which protesters had been using to communicate and plan their actions. However, on Thursday the government ordered a shutdown of Internet communications and mobile-phone networks.

"As a result of widespread disruption to the Internet in Egypt, people there are unable to access Google and YouTube services or at best are having real difficulty doing so," said Scott Rubin, a Google spokesman, via e-mail.

Facebook also confirmed that access to its site is very limited. "We are aware of reports of disruption to service and have seen a drop in traffic from Egypt since Thursday," said Facebook spokesman Andrew Noyes via e-mail.

Many Yahoo users are also affected and the company is monitoring the situation closely, spokeswoman Nina Blackwell said via e-mail. "Yahoo was founded on the principle that access to information can improve people's lives, and we are always concerned when Internet access is denied to people anywhere in the world," she said.

Twitter confirmed on Tuesday that its site and platform applications had been blocked by Egypt. "We believe that the open exchange of information and views benefits societies and helps governments better connect with their people," Twitter said in a statement at the time.